Electrical rectifier



April 25, 1933. c. STROBEL ELECTRICAL RECTIFIER Original Filed Sept. 10,1931

' INVENTOR Clea/#121 hf Szrobel BY dbl-1F HIS ATTORNEY Patented Apr. 25, 1933 ,UNITED STATES PATENT OFFICE OEABLB K. STROBEL, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO-THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVAL-E, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA EECTRICAL RECTIFIER Original application filed September 10, 1931, Serial No. 562,043. Divided and this application filed November 30, 1932.

My invention relates to electrical rectifiers, and particularly to rectifiers employing asymmetric units'of the metal oxide type.

When a rectifier of the type described 1s to be used for rectifying small currents, it is necessary, if the rectifier is to be eflicient, that the units have a high resistance as well as a good rectifying ratio. One way in which the units can be constructed to provide these de-- sirable features is to make them small in physical size. For example, when the rectifier is to carry several mills of current, a unit onetwelfth of an inch in diameter has been found to be very satisfactory. When the units are made small in size, however, considerable difficulty has been experienced in constructing the rectifier in a manner which will 1nsure good, electrical contact with the units, it being necessary in order to obtain good electrical contact, to subject the units to a comparatively high pressure which is distributed substantially uniformly over the units. One objectof my present invention is to provide a rectifier assembly which will insure good electrical contact with the small'asymmetric units, and which at the same time is easy and economical to manufacture.

The present application is a division of my copendin application, Serial No. 562043, filed on pt. 10, 1931, for electrical rectifiers.

I will describe one'form of rectifier embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a view showing in front elevation one form of rectifier embodying my invention. Fig. 2 is an enlarged vertical longitudinal sectional view of the rectifier shown in Fig. 1, with some of the parts in elevation to better illustrate the construction of the rectifier.

Similar reference characters refer to similar parts in both views.

Referring to the'drawing, the rectifier here shown is of the full-wave type, and comprises four asymmetric units A, A, A and A assembled in a suitable hole 35 in an enclosing member B These asymmetric units may be ofany suitable type, but in'the form here shown, each of these units comprises a fiat Serial No. 644,979.

cuprous oxide, formedon one side thereof.

Asymmetric units of the type described exhibit the characteristic of offering a higher resistance to current tending to cop er to the oxide than to current tending to ow in the opposite direction through the unit. The enclosing member B in the embodiment illustrated is in the form of a rectan ular block, and is preferably constructed of rass. It will be readily understood, however, that the enclosing member may have any desired shape and may be constructed of any other suitable metal. The hole 35 extends downwardly from the top of the block to a suitable depth, and has a diameter somewhat larger than the asymmetricunits A. The portion of the block adjacent the left-hand side of the hole 35 as viewed in Fig. 2 is provided with a slot 36 (see Fig. 1) which is the same length as the hole 35, and which extends into the hole 35 throughout its length. The sides of the hole 35 and slot 36 are covered by a piece 50 of suitable insulating material, such as paper, which may be glued or otherwise fastened in place. As will be apparent from an inspection of the draw-' ence character C with a suitable distinguishing exponent, and adjacent the coating 2 of each unit is placed an impressionable conducting plate D. Each conducting spacer C is provided with an integral lug 38 which extends outwardly through the slot 36 to facilitate the making of electrical connections with the units. A pressure disk E is placed adjacent the metal 1 of the upper unit A", and interposed between this pressure disk and a metal cover 39 which closes the upper end of the hole 35 is a compressed coil spring G The cover 39 is fastened to the block B by means of a screw 40 which passes through a flow from the.

suitable clearance hole in the cover, and is threaded into a tapped hole 40- in the block B Also fastened to the block 13 by means of the screw 40 is an insulated terminal board 41 carrying four terminal posts 42, 43, 44 and 45. As will be apparent from an inspection of Fig. 1, the terminal posts 42, 43, 44 and 45 are fastened by means of conductors 46, 47,48 and 49 with the lugs 38 on the conducting spacers C*, 0*, C and C respectively. It will'be understood that since the block 13 is metal, the metalside of the unit A is electrically connected with the conducting disk C through the medium of the pressure disk E the spring G cover 39 and block )3.

In utilizing the rectifier shown in thedrawing, a suitable source pfaalternating current may be connected with the terminal posts 43 and 44, and theload may be connected with the terminal-posts 42 and 45, the terminal post 42 being positive and the terminal post 45 being negative.

It should be pointed out that, while in describing my invention, I have shown only a full-wave rectifier in which each leg of the rectifier consists of, a single asymmetric unit, in actual practice the rectifier may be constructed with as many units in series in each leg as are necessary to enable the rectifier to be operated on the desired electro-motive force.

Although I have herein shown and described only one form of electrical rectifier embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A rectifier comprising a metal block provided with a hole and with a slot which communicates with one side of said hole throughout its length, means for insulating the sides of said hole and said slot, a plurality of asymmetric units in said hole, a plurality of conducting spacers in said hole, one between each two adjacent units and between the bottom of said hole and the adjacent unit and each provided with a lug which extends outwardly through said slot, a pressure disk in said hole adjacent the outer unit, a compression spring having one end engaging the outer side of said pressure disk, and means secured to said block for compressing said spring.

2. A rectifier comprising a metal block provided with a hole and with a slot which communicates with one side of said hole throughout its length, means for insulating the sides of said hole and said slot, aplurality of asymmetric units in said hole, a plurallty of conducting spacers in said hole, one between each two ad acent units and between the bottom of said hole andthe adjacent unit and each provided with a lug which extends outwardly through said slot, a pressure disk in said hole adjacent the outer unit, a compression spring having one end engaging the outer side of.

said pressure disk, and a metal cap secured to said block and compressing said spring.

3. A rectifier comprising a metal block provided with a hole and with a slot which communicates with one side of said hole throughout its length, means for insulating the sides of said hole and said slot, a plurality of asymmetric units in said hole, a plurality of conducting spacers in said hole, one between each two adjacent units and getween the bottom of said hole and the adjacent unit and each provided with a lugtwhich extends outwardly through said slot, a pressure disk in said hole adjacentthe outer unit, a compression spring having one end engaging the outer side of said pressure disk, a metal cap secured to said .block for compressing said spring, a terminal board secured to said block, and a plurality of terminal posts carried'by said board and each electrically connected with a different one of the lugs on said spacers.

4. A rectifier comprising a metal block provided with a hole which extends part way through said block and with a slot which extends into said hole through one side of the block, a plurality of asymmetric units in said hole each comprising a metal disk having a coating of a compound of the metal formed on one side thereof, said disks being disposed in said hole in such manner that the two disks nearest the inner end of the hole have their metal sides facing toward the inner end of the hole and that the two outer disks have their metal sides facing toward the outer end of the hole, a plurality of conducting spacers in said hole, one disposed between each two adjacent units and between the bottom of the hole and the adjacent unit and each having a lu which extends outwardly through said slot, a plurality of impressionable conducting platesin said hole, one adjacent the coating of each unit, a conducting disk in said hole adjacent the metal side of the outermost unit, a coiled spring in said hole adjacent sald conducting disk, a metal cover secured to said block and compressing said spring, an insulating terminal board secured to said block, and a plurality of terminal posts mounted on said terminal board and each connected with the lug on a difierent one of said spacers.

In testimony whereof I affix my signature.

CHARLES K. STROBEL. 

